| Objective:To map out the reference ranges of the ratio of the operative mastoid cavity's volume to cross-sectional opening area of meatoplasty among patients with fully epithelialized time not more than4months after canal-wall-down mastoidectomy(CWD); To investigate the influence factors of the ratio and analyze correlation between the operative mastoid cavity's volume and cross-sectional opening area of meatoplasty.Methods:By collecting167cases of patients who had chronic suppurative otitis media in the department of Otolaryngology of the First Affiliated Hospital of Kunming Medical College from October,2009to April,2011, according to the inclusion and exclusion criteria,111cases were selected. With the retrospective clinical case-note review method, we made feedback tables, measured the operative mastoid cavity volume and the vertical and horizontal diameters of the external acoustic meatus. Then we recorded all information involved. Finally, a database was established and statistical analyses of all data were performed with SPSS17.0software.1. to calculate the95%bilateral medical reference range of the ratio of the operative mastoid cavity volume to the cross-sectional opening area of meatoplasty after CWD among patients with the fully epithelialized time of their operative cavity not more than4months by using the method of normal distribution.2.To explore whether or not there exists a linear correlation between the operative cavity volume and the cross-sectional opening area of meatoplasty among patients with the fully epithelialized time of their operative cavity not more than4months by scatter plot and Pearson correction analysis, if there is linear correlation, get the linear regression equation between them.3. Grouped with the fully epithelialized time,111patients were divided into two groups, namely≤4months subgroup and>4months subgroup, and among≤4months subgroup, patients were classified in terms of age,sex, side of affected ear, type of otitis media, patients ethnic and existence of postoperative complications. Next, all data were tested to show whether they followed a normal distribution. Then, according to their data distribution types, to compare the two-group sample'mean value to show whether or not there is a significant difference by two-independent samples t(t') test or Wilcoxon signed rank test(α=0.05).4. to explore the influential factors of the ratio between the operative mastoid cavity volume and the cross-sectional opening area of meatoplasty by stepwise regression method.Results:1. The95%bilateral medical reference range of the ratio of the operative mastoid cavity volume to cross-sectional opening area of meatoplasty among104patients with the fully epithelialized time of their operative cavity not more than4months was1.41-2.75cm.2.95%confidence interval of above ratio'population mean was2.02-2.14cm.3. There is a linear correlation between the cross-sectional opening area of meatoplasty and the operative mastoid cavity volume in≤4months subgroup (r=0.934, p=0.000), and their linear regression equation is Y=0.422+0.342x,(R=0.934, R2=0.873, t=9.475, P=0.000),if the cross-sectional opening area of meatoplasty is regarded as dependent variable Y, while the operative mastoid cavity volume as independent variable x. Suppose that the vertical diameter of opening area of meatoplasty is equal to its horizontal diameter, the related equation between external meatus diameter and operative mastoid cavity volume is deduced as follow: D=(?).4. There was no significant difference between the fully epithelialized time of operative cavity≤4months subgroup and>4months subgroup with regards to the operative cavity volume and the cross-sectional opening area of meatoplasty by Wilcoxon singed rank test (P=0.259,0.702),and there was no significant difference in the ratio of the operative cavity volume to the cross-sectional opening area of meatoplasty by two-independent samples t-test (P=0.06).5. By age, patients among≤4months subgroup were divided into two teams,<18Y minor team and≥18Y adult team, and there was significant difference between the two teams in the operative cavity volume, the cross-sectional opening area of meatoplasty and the ratio of the operative cavity volume to the cross-sectional opening area of meatoplasty (P=0.000,0.000,0.010), so it is considered that the three aspects above in adult team are bigger than those in minor team; By sex, patients among≤4months subgroup were divided into male team and female team, and there were significant difference between the two teams in the operative cavity volume and the ratio of the operative cavity volume to the cross-sectional opening area of meatoplasty (P=0.044,0.010), while there was no significant difference in the cross-sectional opening area of meatoplasty between two teams, so it was believed that the operative cavity volume and the ratio of the operative cavity volume to the cross-sectional opening area of meatoplasty in male team are greater than those in female team. By side of affected ear, patients among≤4months subgroup were divided into left ear team and right ear team, and there were no significant difference between the two teams in the operative cavity volume, the cross-sectional opening area of meatoplasty and the ratio of the operative cavity volume to the cross-sectional opening area of meatoplasty (P=0.539,0.667,0.422); By type of otitis media, patients among≤4months subgroup were divided into cholesteatoma type team and granulation type team, there were significant difference between the two teams in the operative cavity volume and the cross-sectional opening area of meatoplasty (P=0.011,0.007), while there was no significant difference in ratio of the operative cavity volume to cross-sectional opening area of meatoplasty between two teams, so it was deemed that the operative cavity volume and the cross-sectional opening area of meatoplasty in cholesteatoma type team are greater than those in granulation type team. By patients ethnic, patients among≤4months subgroup were divided into Han team and minority team, and there were no significant difference between the two teams in the operative cavity volume, the cross-sectional opening area of meatoplasty and the ratio of the operative cavity volume to the cross-sectional opening area of meatoplasty (P=0.617,0.397,0.277); According to postoperative complications, patients among≤4months subgroup were divided into team with complications and team without complications, and there were significant difference between the two teams in the operative cavity volume and the cross-sectional opening area of meatoplasty (P=0.000,0.001), while there was no significant difference in the ratio of the operative cavity volume to the cross-sectional opening area of meatoplasty between two teams (P=0.457), so it was believed that the operative cavity volume and the cross-sectional opening area of meatoplasty in team with complications are greater than those in team without complications.6,If V/S is regarded as dependent variable and age, sex, side of affected ear, type of otitis media, patients ethnic and postoperative complications are regarded as independent variables, sex and age were selected as the influence factors of the ratio of the operative mastoid cavity volume to the cross-sectional opening area of meatoplasty and the former is more influential than the later, and the linear regression equation is V/S=1.747+0.204×sex+0.006×age。Conclusion:1.In the study, we establish95%bilateral reference range (1.41-2.75cm) for the ratio of the operative mastoid volume to the cross-sectional opening area of meatoplasty after CWD among patients with the fully epithelialized time of the operative cavity not more than4months and the95%confidence interval (2.02-2.14cm) of its population mean.2. There is a postive linear correlation between the cross-sectional opening area of meatoplasty and the operative mastoid cavity volume, at the same time, linear regression equation (Y=0.422+0.342x) is established between them and the equation (D=0.563+0.436V) is deduced between the diameter of opening area of meatoplasty and the operative mastoid cavity volume.3. There are two factors:sex and age, influencing the ratio of the operative mastoid cavity volume to the cross-sectional opening area of meatoplasty and the former is more influential than the later, and the ratio was greater in adults than in minors, and greater in males than in females. The study showed that the ratio had no bearing on the factors such as side of affected ear, types of otitis media, patients ethnic and existence of postoperative complications. |
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